Narrowband IQ extraction and storage

ABSTRACT

Capturing, extracting and storing narrowband IQ data for later processing enables timely and efficient analysis. As wideband capture of RF information includes noise and non-signal elements, the present invention detects, extracts and stores narrowband IQ signals for later assessment. By transforming a high-volume data stream to a collection of smaller narrowband signals with greatly reduced storage and on-board processing requirements the present invention facilitates the capability to analyze signals of interest in an otherwise denied environment.

RELATED APPLICATION

The present application relates to and claims the benefit of priority toU.S. Provisional Patent Application No. 62/963,373 filed 20 Jan. 2020which is hereby incorporated by reference in its entirety for allpurposes as if fully set forth herein.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present invention relate, in general, to the captureand storage of Radio Frequency (RF) data and more particularly toextraction and storage of narrowband IQ data.

Relevant Background

At any one moment in time, the RF spectrum contains a vast amount ofinformation. As the use of the RF spectrum to transport data grows sotoo does the interest in capturing and analyzing such data. The amountof data collected in what is referred to as wideband RF capture is basedon an amount of the RF spectrum observed through a sampling rate (or howmuch data is taken within a given time frame). For example, the sameamount of data may be collected through a high sampling rate over asmall bandwidth as with a high bandwidth (spectrum) but with a lowsampling rate.

As data collection increases so too do the requirements of processingpower and storage leading to tradeoffs between storage time,responsiveness, processing speed, and even size, weight and power ofequipment.

Not all information in the RF spectrum is useful information. Most ofthe RF information acquired while performing a wideband capturedescribes background noise/non-signal data. For example, to capture the2.4 GHz band (from 2.4 GHz to 2.5 GHz) requires a minimum capture of 100million complex samples (also known as I/Q (In-phase/Quadrature) samplesper second. With a 16-bit Analog-to-Digital Converter (ADC), this isequivalent to 400 Megabytes per second of data which is both cumbersometo store and to process.

High volume data storage and portability is also a challenge despite therecent efforts to compress and manage large files. Large data files arecumbersome with which to interact over a network, difficult to transferand problematic to analyze. In many instances the time and resources totransfer a large wideband recording, even when compressed, exceeds thetime and resources required to capture the data. And the reconstitutionof a compressed file further adds to resource requirements, time delaysand data loss.

What is needed is a highly available datastore of select, narrowband I/Qdata from signals of interest alongside the metadata and envelopparameters used to capture and extract such data. The challengetherefore is to identify signals from what is otherwise noise andefficiently store such data for near-real time analysis. These and otherdeficiencies of the prior art are addressed by one or more embodimentsof the present invention.

Additional advantages and novel features of this invention shall be setforth in part in the description that follows, and in part will becomeapparent to those skilled in the art upon examination of the followingspecification or may be learned by the practice of the invention. Theadvantages of the invention may be realized and attained by means of theinstrumentalities, combinations, compositions, and methods particularlypointed out in the appended claims.

SUMMARY OF THE INVENTION

High-volume RF data is transformed to a collection of smaller narrowbandsignals with greatly reduced storage and on-board processingfacilitating the capability to analyze signals of interest in otherwisedenied environments. A computer implemented system for IQ dataextraction and storage includes, according to one embodiment of thepresent invention a digital sampling device configured to acquire timedomain IQ data communicatively coupled to a data conversion module. Thedigital conversion module is configured to convert time domain IQ datacollected the sampling device to frequency domain IQ data.

The system further includes a signal detection module communicativelycoupled to the data conversion module configured to detect time andfrequency envelope parameters from the frequency domain IQ data. Basedon select time and frequency envelope parameters an extraction module,communicatively coupled to the signal detection module, is configured toextract narrowband IQ signal components from the frequency domain IQdata. In some instances of the present invention, the time and frequencyenvelope parameters include signal edges and ranges. Lastly, anon-transitory storage media is configured to receive and store theextracted narrowband IQ signal components.

In other embodiments of the present invention, the system for IQ dataextraction and storage, the digital sampling device is a softwaredefined radio which itself include the data conversion module. Thesystem for IQ data extraction and storage can also include anon-transitory data storage buffer communicatively coupled to thedigital sampling device and the extraction module. This storage buffercan be configured to receive, and store acquired time domain IQ data forlater processing.

In other versions of the present invention the signal detection moduleincludes instructions executable by a processor to segment and separatefrequency domain IQ data from noise.

The system for IQ data extraction and storage of the present inventionmay also include a formatting module wherein the formatting moduleassociates extracted narrowband IQ signal components with the time andfrequency envelope parameters. In doing so the formatting moduleincludes instructions executable by a processor to tag extractednarrowband IQ signal components with time and frequency envelopeparameters.

In other versions of the present invention the extraction moduleincludes instructions executable by a processor to digitally downconvert time domain IQ data including instructions to frequency shiftand down sample the frequency domain IQ data to extract a narrowband IQof a narrow signal. In other versions of the present invention theextraction module includes instructions executable by a processor topolyphase resample frequency domain IQ data. These processes may be doneby a graphic, central processing unit, or in some cases an FPGA.

A method for IQ data extraction and storage, according to one embodimentof the present invention, begins by acquiring IQ time domain data by adigital sampling device. The time domain IQ data is thereafter convertedto frequency domain IQ data. From that frequency domain IQ data time andfrequency envelope parameters are detected leading to the extraction ofnarrowband IQ signal components based on select time and frequencyenvelope parameters. The method concludes by receiving and storing, at anon-transitory storage media, the extracted narrowband IQ signalcomponents.

Other aspects of a method IQ data extraction and storage includebuffering acquired IQ data for later processing. Another aspect of themethodology of present invention is segmenting and separating frequencydomain IQ data from noise and associating extracted narrowband IQ signalcomponents with time and frequency envelope parameters. The time andfrequency envelope parameters can include signal edges and ranges.

Extracting narrowband IQ signals can, according to another version ofthe present invention, include digitally down converting time domain IQdata as well as digitally down converting, frequency shifting and downsampling frequency domain IQ data. Extracting can also include polyphaseresampling frequency domain IQ data.

The features and advantages described in this disclosure and in thefollowing detailed description are not all-inclusive. Many additionalfeatures and advantages will be apparent to one of ordinary skill in therelevant art in view of the drawings, specification, and claims hereof.Moreover, it should be noted that the language used in the specificationhas been principally selected for readability and instructional purposesand may not have been selected to delineate or circumscribe theinventive subject matter; reference to the claims is necessary todetermine such inventive subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned and other features and objects of the presentinvention and the manner of attaining them will become more apparent,and the invention itself will be best understood, by reference to thefollowing description of one or more embodiments taken in conjunctionwith the accompanying drawings, wherein:

FIGS. 1A-1D depict two and three-dimensional renderings of RF signals aswould be known to on skilled in the relevant art;

FIG. 2 presents a high-level block diagram and data flow architecturefor narrowband IQ data extraction and storage according to oneembodiment of the present invention;

FIG. 3 is a flowchart of one methodology according the present inventionfor narrowband IQ data extraction and storage;

FIG. 4 is one embodiment of asset/resource allocation for the presentinvention of narrowband IQ data extraction and storage;

FIG. 5 is a block diagram of a computer system suitable forimplementation of one or more embodiments of narrowband IQ dataextraction and storage.

The Figures depict embodiments of the present invention for purposes ofillustration only. Like numbers refer to like elements throughout. Inthe figures, the sizes of certain lines, layers, components, elements orfeatures may be exaggerated for clarity. Moreover, one skilled in theart will readily recognize from the following discussion thatalternative embodiments of the structures and methods illustrated hereinmay be employed without departing from the principles of the inventiondescribed herein.

DESCRIPTION OF THE INVENTION

Capturing, extracting and storing narrowband IQ data for laterprocessing enables timely and efficient analysis. As wideband capture ofRF information includes noise and non-signal elements, the presentinvention detects, extracts and stores narrowband IQ signals for laterassessment. By transforming a high-volume data stream to a collection ofsmaller narrowband signals with greatly reduced storage and on-boardprocessing requirements, the present invention facilitates thecapability to analyze signals of interest in an otherwise deniedenvironment.

Embodiments of the present invention are hereafter described in detailwith reference to the accompanying Figures. Although the invention hasbeen described and illustrated with a certain degree of particularity,it is understood that the present disclosure has been made only by wayof example and that numerous changes in the combination and arrangementof parts can be resorted to by those skilled in the art withoutdeparting from the spirit and scope of the invention.

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the present invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. Also, descriptions of well-known functions and constructionsare omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of exemplary embodiments of thepresent invention are provided for illustration purpose only and not forthe purpose of limiting the invention as defined by the appended claimsand their equivalents.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Thus, for example, reference to “a component surface”includes reference to one or more of such surfaces.

As used herein any reference to “one embodiment” or “an embodiment”means that a particular element, feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. The appearances of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

It will be also understood that when an element is referred to as being“on,” “attached” to, “connected” to, “coupled” with, “contacting”,“mounted” etc., another element, it can be directly on, attached to,connected to, coupled with or contacting the other element orintervening elements may also be present. In contrast, when an elementis referred to as being, for example, “directly on,” “directly attached”to, “directly connected” to, “directly coupled” with or “directlycontacting” another element, there are no intervening elements present.It will also be appreciated by those of skill in the art that referencesto a structure or feature that is disposed “adjacent” another featuremay have portions that overlap or underlie the adjacent feature.

As used herein, the following terms are understood to have the meaning:

-   -   ADC—Analog to Digital converter—the part of an SDR that converts        analog voltages (like those originating from an antenna) to a        sequence of numeric values.    -   Bandwidth—A range of frequencies within a given band, in        particular that used for transmitting a signal.    -   DDC (Digital Down Conversion)—is a technique that takes a band        limited high sample rate digitized signal, mixes the signal to a        lower frequency and reduces the sample rate while retaining all        the information.    -   DSP (Digital Signal Processing)—the use of digital processing,        such as by computers or more specialized digital signal        processors, to perform a wide variety of signal processing        operations.    -   Envelope Parameter—Envelope parameters or “signal extents”        define a range in which a signal lies in the time and frequency        domains. For example, By specifying this signal started at 20        seconds into a recording/stream and ended at 20.5 seconds,        within the frequency range of 101 and 101.1 MHz, the        extents/parameters needed to fully contain the signal are        specified.    -   FFT (Fast Fourier Transform)—A Digital Signal processing        function that is used to convert time series information into a        series of frequencies, by arranging the periodicity of the data        into a series of bins representing a range of frequencies.    -   FPGA (Field-Programmable Gate Array)—an integrated circuit        designed to be configured by a customer or a designer after        manufacturing.    -   GPU (Graphics Processing Unit)—is a specialized electronic        circuit designed to rapidly manipulate and alter memory to        accelerate the creation of images in a frame buffer intended for        output to a display device. Their highly parallel structure        makes them more efficient than general-purpose central        processing units (CPUs) for algorithms that process large blocks        of data in parallel.    -   I/Q Samples/data (In-phase and Quadrature Modulated        Samples)—often used in RF applications, form the basis of        complex RF signal modulation and demodulation, both in hardware        and in software, as well as in complex signal analysis. In        electrical engineering, a sinusoid with angle modulation can be        decomposed into, or synthesized from, two amplitude-modulated        sinusoids that are offset in phase by one-quarter cycle (π/2        radians). All three functions have the same center frequency.        These amplitude modulated sinusoids are known as the in-phase        and quadrature components. I is the In-Phase signal component        while Q is the Quadrature signal component.    -   Narrowband—Describes a sampled capture or single signal (or        aggregate of subchannels) that occupies a relatively small        bandwidth. For the purposes of this document, signals that are        less than 20 MHz (e.g. a 10 MHz LTE channel or a 200 kHz FM        radio broadcast) would be considered Narrowband.    -   RBW (Resolution Bandwidth)—In frequency domain data, this is the        minimum frequency unit discernible. For example, to reliably        detect lower power signals with a bandwidth of 1 MHz, the        resolution bandwidth of should be ideally lower than 1 MHz.    -   RF—Radio Frequency—Used for wireless communications, and        physical sensing, RF Energy is one form of electromagnetic        energy which consists of waves of electric and magnetic energy        moving together (radiating) through space, oscillating at        various rates. The area where these waves are found is called an        electromagnetic field.    -   RF Spectrum (aka Radio Spectrum)—The part of the electromagnetic        spectrum with frequencies from 30 hertz to 300 GHz.        Electromagnetic waves in this frequency range, called radio        waves, are widely used in modern technology, particularly in        telecommunications.    -   Sampling Rate—A description of how many times per second an RF        signal is sampled    -   Signal of Interest (SOI): SOI is the signal or waveform that is        of interest to the end user and is being retained as part of the        narrowband IQ process described in this document.    -   Software Defined Radio—(SDR) a radio communication system where        components that have been traditionally implemented in hardware        are instead implemented by means of software    -   SWaP: Size, Weight, and Power    -   Wideband—Describes a sampled capture or single signal (or        aggregate of subchannels) that occupies a large bandwidth. For        the purposes of this document, radio captures that are greater        than 20 MHz (e.g. a 50 MHz WBT capture) would be considered        Narrowband.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the specification andrelevant art and should not be interpreted in an idealized or overlyformal sense unless expressly so defined herein. Well-known functions orconstructions may not be described in detail for brevity and/or clarity.

Included in the description are flowcharts depicting examples of themethodology which may be used to extract and store IQ data. In thefollowing description, it will be understood that each block of theflowchart illustrations, and combinations of blocks in the flowchartillustrations, can be implemented by computer program instructions.These computer program instructions may be loaded onto a computer orother programmable apparatus to produce a machine such that theinstructions that execute on the computer or other programmableapparatus create means for implementing the functions specified in theflowchart block or blocks. These computer program instructions may alsobe stored in a computer-readable memory that can direct a computer orother programmable apparatus to function in a particular manner suchthat the instructions stored in the computer-readable memory produce anarticle of manufacture including instruction means that implement thefunction specified in the flowchart block or blocks. The computerprogram instructions may also be loaded onto a computer or otherprogrammable apparatus to cause a series of operational steps to beperformed in the computer or on the other programmable apparatus toproduce a computer implemented process such that the instructions thatexecute on the computer or other programmable apparatus provide stepsfor implementing the functions specified in the flowchart block orblocks.

Accordingly, blocks of the flowchart illustrations support combinationsof means for performing the specified functions and combinations ofsteps for performing the specified functions. It will also be understoodthat each block of the flowchart illustrations, and combinations ofblocks in the flowchart illustrations, can be implemented by specialpurpose hardware-based computer systems that perform the specifiedfunctions or steps, or combinations of special purpose hardware andcomputer instructions.

Some portions of this specification are presented in terms of algorithmsor symbolic representations of operations on data stored as bits orbinary digital signals within a machine memory (e.g., a computermemory). These algorithms or symbolic representations are examples oftechniques used by those of ordinary skill in the data processing artsto convey the substance of their work to others skilled in the art. Asused herein, an “algorithm” is a self-consistent sequence of operationsor similar processing leading to a desired result. In this context,algorithms and operations involve the manipulation of informationelements. Typically, but not necessarily, such elements may take theform of electrical, magnetic, or optical signals capable of beingstored, accessed, transferred, combined, compared, or otherwisemanipulated by a machine. It is convenient at times, principally forreasons of common usage, to refer to such signals using words such as“data,” “content,” “bits,” “values,” “elements,” “symbols,”“characters,” “terms,” “numbers,” “numerals,” “words”, or the like.These specific words, however, are merely convenient labels and are tobe associated with appropriate information elements.

Unless specifically stated otherwise, discussions herein using wordssuch as “processing,” “computing,” “calculating,” “determining,”“presenting,” “displaying,” or the like may refer to actions orprocesses of a machine (e.g., a computer) that manipulates or transformsdata represented as physical (e.g., electronic, magnetic, or optical)quantities within one or more memories (e.g., volatile memory,non-volatile memory, or a combination thereof), registers, or othermachine components that receive, store, transmit, or displayinformation.

Upon reading this disclosure, those of skill in the art will appreciateadditional alternative structural and functional designs for a systemand a process for IQ data extraction and storage through the disclosedprinciples herein. Thus, while particular embodiments and applicationshave been illustrated and described, it is to be understood that thedisclosed embodiments are not limited to the precise construction andcomponents disclosed herein. Various modifications, changes andvariations, which will be apparent to those skilled in the art, may bemade in the arrangement, operation and details of the method andapparatus disclosed herein without departing from the spirit and scopeof the invention.

I/Q data is a precise representation of a RF signal. Typicaltwo-dimensional representation of a RF signal fails to provide keyinformation that is necessary to fully understand and analyze signaldata. FIGS. 1A-1D provide a graphical perspective of a I/Q or truerepresentation of signal that may be compared to a more commontwo-dimensional representation. FIG. 1A is a typical two—dimensionalsinusoidal signal 110 representation. While it is seemingly telling ofinformation such as amplitude and frequency, it is, in reality, quitelacking.

FIG. 1B presents the same signal 110 yet in an I/Q three-dimensionalperspective. The signal it actually a corkscrew. Looking at the signalin FIG. 1B from the side produces the same image as FIG. 1A (I data)however viewing the signal of FIG. 1B from the top provides an entirelydifferent image (Q data). And if viewed down axis, the signal becomes acircle in which a signal propagating clockwise is a positive whilepropagating counterclockwise is a negative signal. Indeed, the view ofthe signal down axis presents a polar coordinate image of how the signalpropagates. I/Q data is therefore a rectangular representation of asignal's polar notation. In most instances the rectangular notation ofI/Q data is used due to the ease of hardware implementations. In itsbasic format I/Q data comprises a vector component and a complex number,I+Qi.

FIGS. 1C and 1D present a two-dimensional and three dimensional I/Qrepresentation, respectively, of a more complex signal 120. One ofreasonable skill in the relevant art will appreciate there are differentways to represent the same I/Q data sample. These methodologies are wellknown and will not be further discussed herein. A true signal iscomplex. It possesses attributes of phase, amplitude and time. Thesefeatures, for select extracted signals, are the focus of the presentinvention.

One embodiment of the present invention detects, isolates and extractsIQ data from noise and thereafter stores the same for data retention,playback and further processing. The present invention makes use ofcaptured wideband data by isolating signals from noise and storingnarrowband IQ information in a highly accessible database. Oneembodiment of the present invention transforms a single high volume datastream into a collection of smaller narrowband signals that have greatlyreduced data storage, on-board processing requirements. Such narrowbanddata facilitates the capability to analyze signals on a dismounted,stand-alone unit operating in an environment lacking network or largercommunications and processing capabilities.

FIG. 2 is a high-level block diagram of a system 200 for narrowband IQdata extraction and storage according to one embodiment of the presentinvention. RF data is typically streaming data meaning that it iscontinuously being generated by different sources and received in anaggregate form. Collection, storage and analysis of such data isconducted over a set period of time. As one of reasonable skill in therelevant art can appreciate the volume of collected streaming data inany environment can be significant. Streaming data differs from batchdata analysis in which processing can be used to compute arbitraryqueries over different sets of data. In batched data analysis resultsare derived from all the data it encompasses enabling deep analysis ofbig data sets at the expense of real time results. Streaming analysisrequires a more focused efficient process but often does so at the pricein-depth analysis.

As streaming data is continuous but efficient analysis is batched, aportion of streaming data is selected for examination, with the processby which the selection of signals to be examined becoming a criticalcomponent. The portion, which is normally based on time but may be basedon other parameters, is selected in consideration of the need formeaningful results and the speed by which processing can occur. Forexample, the volume of data can be used as a selection criteria ratherthan a particular period of time. A larger sampling may provideadditional information and more reliable, meaningful results but at theexpense of delayed delivery of those outcomes. A shorter interval may beprocessed quickly yet yield results that are inconclusive. It isrelevant that an objective of the present invention is to perform IQextraction and storage process with maximum efficiency using variousstrategies such as parallelism and data pipelining to distribute thework throughout various parts of the system to provide meaningful yettimely results.

The present invention, according to one embodiment, captures data by wayof a digital sampling device such as a software defined radio 210. Whilethe resources of a software defined radio aid in the implementation ofthe present invention, one of reasonable skill in the relevant art willappreciate that other means by which to capture RF signal and IQ dataare available and are within the scope of the present invention.

As shown in FIG. 2 data is captured by a software defined radio 210 orsimilar digital sampling device from various sources. The radio in thisembodiment provides high precision time stamped data describing the timeseries in an I/Q data format. In one version of the invention datacapture by the radio 210 is stored (buffered) 215 as RAM or high-speedSSD based storage in a manner that allows for rapid time indexing.

This aspect of the present invention provides for rapid, random accessto large stores of RAM and disk-based IQ data collection platforms. Suchspecialized storage and retrieval mechanisms reduce access time to storeand retrieve the IQ data, allowing additional time to perform thesubsequent conversions and processing as needed to detect and extractthe narrowband signals. As shown in FIG. 2 the buffering process is inparallel to other methodologies for narrowband extraction. Upon learningenvelope parameters for select signals, data resident in the buffer canbe quickly ascertained/retrieved for subsequent analysis.

Once collected, IQ data is converted to the frequency domain data. Inone embodiment of the present invention this conversion is accomplishedwith a spectrum generation/data conversion module 220 resident in thesoftware defined radio using a high-speed FPGA (Hardware Accelerated)based Fast Fourier Transform (FFT) function to deliver time-stampedspectrum data. In other embodiments the conversion utilizes a GraphicProcessor Unit (GPU) 230 (shown in FIG. 2), an additional FPGA or thelike to carry out the conversion steps. The conversion of IQ data intothe frequency domain sets readies data for the signal detection step ofprocessing. In doing so, timestamps of the spectrum information areaccurately aligned with the source IQ data ensuring that the extractionoperation is completed successfully.

Recognize there is a tradeoff between resolution bandwidth and timeresolution. Generally (while keeping the data storage requirements thesame), the finer the signal detail looked for in time, the more coursethe frequency measurements will be and vice versa. The present inventionoptimizes data collection with storage based on ongoing determination ofenvelope parameters.

A signal detection module 235 receives frequency domain data in spectrumsnapshots from which it identifies signals embedded within the RFenvironment. These snapshots are batch processed by, in one embodiment,a GPU 230 accelerated detection/segmentation process. This processbuilds an estimate of the noise floor providing a threshold to separatethe signal(s) from the noise. Concurrently the signal detection module235 ascertains envelope parameters defining edges of signals (i.e.,frequency and time ranges). In one version of the present invention thesignal detection process is akin to an image segmentation algorithm,analyzing the frequency domain snapshots over time as a 2-dimensionalimage. While such processing can take place in parallel using a GPU,further acceleration is possible with an FPGA optimized implementation.

An extraction module 240 receives, in one instance raw IQ data captureby and time-tagged by the software defined radio 210 via the buffer 215,and, in another instance, detected signals from the detection module235. From this data narrowband signal components are extracted. Theextraction process first moves through the collection of envelopeparameters identified by the signal detection module 235, identifyingthe begin and end timestamps of each signal segment while loading thenecessary time ranges. Any “dead space” or time periods where there areno signals present are disregarded and not processed further.

For each set of signal envelope parameters, IQ data samples are putthrough a digital down conversion process wherein the signal isfrequency shifted and downsampled extracting the narrowband IQ of thenow narrowed signal.

In one embodiment of the present invention the digital down conversionprocess is accomplished using a GPU 230. In such an approach digitaldown conversion is implemented through accelerated complex sinusoidgeneration and complex multiplication combined with a Finite ImpulseResponse (FIR) filter and decimation. Recall a finite Impulse ResponseFilter is a filter whose impulse response (or response to any finitelength input) is of finite duration, because it settles to zero infinite time. This is in contrast to Infinite Impulse Response (IIR)filters, which may have internal feedback and may continue to respondindefinitely. Similarly, to decimate a filtered signal by M means tokeep only every Mth sample.

The GPU can also digitally down convert signals using a polyphaseresampling implementation, or a frequency domain based down conversion,the later being potentially faster since a FFT has already occurred atthis point-recognizing that a frequency based down conversion willdestroy phase information.

Digital down conversion can also be accomplished, according to anotherembodiment of the present invention, using a FPGA. By using a FPGA awork-pipeline can be established exploiting hard coded gates for thepurpose of performing DDC operations in a rapid sequential (and orparallelized) manner. In the same manner polyphase resampling can beimplemented using a FPGA providing efficient (albeit somewhatinflexible) DDC. It is worth noting that some degree of filtering canoccur at this stage to minimize total processing time. For example, ifthe system operator does not have a use for signals that match/do notmatch a certain length or bandwidth profile, the present invention cansimply choose to only process the relevant signals.

The use of a GPU or FPGA for digital down conversion depends on thecapabilities and goals of the system and any tradeoffs that have to beconsidered. For example, when phase information needs to be preserved,then the down-conversion processes may become less efficient byinjecting latency at this stage of processing. An example of this wouldbe the angle-of arrival calculations needed for radio direction-findingapplications. Considerations such as these may drive the implementationof the present invention to use a GPU vs an FPGA or vice versa orutilize an entirely different type of computational resource.

One objective of the present invention is to provide an easilyaccessible database of narrowband IQ data for further analysis. Thisobjective is achieved by storage of narrowband IQ and associatedinformation as a time tagged record in a NoSQL/document store styledatabase 270. This record keeping facilitates addition of supplementaldata at a later time as well as the ability to add additional referencesto other signal constructs (such as the determination that the signal isa piece of a larger signal, such as a pulse that is part of a frequencyagile signal). Once stored in this fashion, such data allows signalinformation to be processed easily and more effectively both locally tothe local SDR platform, or over a network.

A formatting module 260 interacts with the digitally down converted IQdata to tag each record and properly format the data for storage.Typically formatting of this type is accomplished with a generalmicroprocessor 265. In addition to preparing IQ data for storage,envelope parameters identified during the detection phase are similarlystored in the database 270 housed on a non-transitory storage mediafacilitating later investigative processes 280.

Additional understanding of the present invention can be gained withattention drawn to FIGS. 3 and 4. FIG. 3 is a flow chart of oneembodiment of a process for IQ data extraction and storage while FIG. 4provides an example of implementation processes and resource allocation.As described previously IQ data extraction and storage begins withacquiring 310 IQ data 400. In one embodiment IQ data 410 is collectedusing a software defined radio 310 while in other embodiments timedomain IQ samples can be acquired from a digitizer or a digital samplingdevice.

Once acquired time domain IQ data 410 is both buffered 320 andseparately converted 330 to frequency domain IQ data. In one embodimentthe frequency domain IQ data 420 is processed to detect 340 time andfrequency envelope parameters 430 of signals. The detection 340 ofenvelope parameters 430 leads to the extraction 350 of IQ signalsgaining narrowband IQ data 450. The detection 340 of envelope parameters430 and extraction 350 of IQ signals 450 based on these parameters canbe implemented in one embodiment by a GPU 230 while in other embodimentsthese processes can be accomplished by a FPGA.

The extracted narrowband IQ signals 450 are formatted 360 and stored 370as a database record 460 in a database along with the envelopeparameters and detection models used to gain such information. Theprocess concludes with post processing 380 the narrowband signals byaccessing the narrowband IQ database.

The ability to sense important signals of interest (SOIs) in a crowdedspectrum has become more and more difficult. As spectrum density grows,understanding what is in your environment at any given time has becomeincreasingly complex.

Background characterization and spectrum monitoring requirements havedriven the need for complete and precise coverage of the spectrum andaccomplishing this with traditional RF acquisition systems has becomeprohibitively expensive and inefficient. Capturing, extracting andstoring narrowband IQ data for later processing enables timely andefficient analysis. As wideband capture of RF information includes noiseand non-signal the present invention detects and extracts IQ signals forlater assessment. Transforming a high-volume data stream to a collectionof smaller narrowband signals with greatly reduced storage and on-boardprocessing requirements facilitates the capability to analyze signals ofinterest in an otherwise denied environment.

One of reasonable skill will also recognize that portions of the presentinvention may be implemented on a conventional or general-purposecomputer system, such as a personal computer (PC), server, a laptopcomputer, a notebook computer, a handheld or pocket computer, and/or aserver computer. FIG. 5 is a very general block diagram of a computersystem in which software-implemented processes of the present inventionmay be embodied. As shown, system 500 comprises a central processingunit(s) (CPU) or processor(s) 501 coupled to a random-access memory(RAM) 502, a graphics processor unit(s) (GPU) 520, a read-only memory(ROM) 503, a keyboard or user interface 506, a display or video adapter504 connected to a display device 505, a removable (mass) storage device515 (e.g., floppy disk, CD-ROM, CD-R, CD-RW, DVD, or the like), a fixed(mass) storage device 516 (e.g., hard disk), a communication (COMM)port(s) or interface(s) 510, and a network interface card (NIC) orcontroller 511 (e.g., Ethernet). Although not shown separately, a realtime system clock is included with the system 500, in a conventionalmanner.

CPU 501 comprises a suitable processor for implementing the presentinvention. The CPU 501 communicates with other components of the systemvia a bi-directional system bus 520 (including any necessaryinput/output (I/O) controller 507 circuitry and other “glue” logic). Thebus, which includes address lines for addressing system memory, providesdata transfer between and among the various components. Random-accessmemory 502 serves as the working memory for the CPU 501. The read-onlymemory (ROM) 503 contains the basic input/output system code (BIOS)—aset of low-level routines in the ROM that application programs and theoperating systems can use to interact with the hardware, includingreading characters from the keyboard, outputting characters to printers,and so forth.

Mass storage devices 515, 516 provide persistent storage on fixed andremovable media, such as magnetic, optical, or magnetic-optical storagesystems, flash memory, or any other available mass storage technology.The mass storage may be shared on a network, or it may be a dedicatedmass storage. As shown in FIG. 5, fixed storage 516 stores a body ofprogram and data for directing operation of the computer system,including an operating system, user application programs, driver andother support files, as well as other data files of all sorts.Typically, the fixed storage 516 serves as the main hard disk for thesystem.

In basic operation, program logic (including that which implementsmethodology of the present invention described below) is loaded from theremovable storage 515 or fixed storage 516 into the main (RAM) memory502, for execution by the CPU 501. During operation of the programlogic, the system 500 accepts user input from a keyboard and pointingdevice 506, as well as speech-based input from a voice recognitionsystem (not shown). The user interface 506 permits selection ofapplication programs, entry of keyboard-based input or data, andselection and manipulation of individual data objects displayed on thescreen or display device 505. Likewise, the pointing device 508, such asa mouse, track ball, pen device, or the like, permits selection andmanipulation of objects on the display device. In this manner, theseinput devices support manual user input for any process running on thesystem.

The computer system 500 displays text and/or graphic images and otherdata on the display device 505. The video adapter 504, which isinterposed between the display 505 and the system's bus, drives thedisplay device 505. The video adapter 504, which includes video memoryaccessible to the CPU 501, provides circuitry that converts pixel datastored in the video memory to a raster signal suitable for use by acathode ray tube (CRT) raster or liquid crystal display (LCD) monitor. Ahard copy of the displayed information, or other information within thesystem 500, may be obtained from the printer 517, or other outputdevice.

The system itself communicates with other devices (e.g., othercomputers) via the network interface card (NIC) 511 connected to anetwork (e.g., Ethernet network, Bluetooth wireless network, or thelike). The system 500 may also communicate with local occasionallyconnected devices (e.g., serial cable-linked devices) via thecommunication (COMM) interface 510, which may include a RS-232 serialport, a Universal Serial Bus (USB) interface, or the like. Devices thatwill be commonly connected locally to the interface 510 include laptopcomputers, handheld organizers, digital cameras, and the like.

As will be understood by those familiar with the art, that the inventionmay be embodied in other specific forms without departing from thespirit or essential characteristics thereof. Likewise, the particularnaming and division of the modules, managers, functions, systems,engines, layers, features, attributes, methodologies, and other aspectsare not mandatory or significant, and the mechanisms that implement theinvention or its features may have different names, divisions, and/orformats. Furthermore, as will be apparent to one of ordinary skill inthe relevant art, the modules, managers, functions, systems, engines,layers, features, attributes, methodologies, and other aspects of theinvention can be implemented as software, hardware, firmware, or anycombination of the three. Of course, wherever a component of the presentinvention is implemented as software, the component can be implementedas a script, as a standalone program, as part of a larger program, as aplurality of separate scripts and/or programs, as a statically ordynamically linked library, as a kernel loadable module, as a devicedriver, and/or in every and any other way known now or in the future tothose of skill in the art of computer programming. Additionally, thepresent invention is in no way limited to implementation in any specificprogramming language, or for any specific operating system orenvironment. Accordingly, the disclosure of the present invention isintended to be illustrative, but not limiting, of the scope of theinvention, which is set forth in the following claims.

In a preferred embodiment, the present invention can be implemented insoftware. Software programming code which embodies the present inventionis typically accessed by a microprocessor from long-term, persistentstorage media of some type, such as a flash drive or hard drive. Thesoftware programming code may be embodied on any of a variety of knownmedia for use with a data processing system, such as a diskette, harddrive, CD-ROM, or the like. The code may be distributed on such media ormay be distributed from the memory or storage of one computer systemover a network of some type to other computer systems for use by suchother systems. Alternatively, the programming code may be embodied inthe memory of the device and accessed by a microprocessor using aninternal bus. The techniques and methods for embodying softwareprogramming code in memory, on physical media, and/or distributingsoftware code via networks are well known and will not be furtherdiscussed herein.

Generally, program modules include routines, programs, objects,components, data structures and the like that perform particular tasksor implement particular abstract data types. Moreover, those skilled inthe art will appreciate that the invention can be practiced with othercomputer system configurations, including hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network PCs, minicomputers, mainframe computers, and thelike. The invention may also be practiced in distributed computingenvironments where tasks are performed by remote processing devices thatare linked through a communications network. In a distributed computingenvironment, program modules may be located in both local and remotememory storage devices.

While there have been described above the principles of the presentinvention in conjunction with IQ data collection, extraction andstorage, it is to be clearly understood that the foregoing descriptionis made only by way of example and not as a limitation to the scope ofthe invention. Particularly, it is recognized that the teachings of theforegoing disclosure will suggest other modifications to those personsskilled in the relevant art. Such modifications may involve otherfeatures that are already known per se and which may be used instead ofor in addition to features already described herein. Although claimshave been formulated in this application to particular combinations offeatures, it should be understood that the scope of the disclosureherein also includes any novel feature or any novel combination offeatures disclosed either explicitly or implicitly or any generalizationor modification thereof which would be apparent to persons skilled inthe relevant art, whether or not such relates to the same invention aspresently claimed in any claim and whether or not it mitigates any orall of the same technical problems as confronted by the presentinvention. The Applicant hereby reserves the right to formulate newclaims to such features and/or combinations of such features during theprosecution of the present application or of any further applicationderived therefrom.

The invention claimed is:
 1. A computer implemented system for IQ dataextraction and storage, the system comprising: a digital sampling deviceconfigured to acquire time domain IQ data from a data stream of highvolume data; a non-transitory data storage buffer communicativelycoupled to the digital sampling device configured to receive, and storeacquired time domain IQ data; a data conversion module communicativelycoupled to the digital sampling device and in parallel with thenon-transitory data storage buffer configured to convert a portion ofthe time domain IQ data to frequency domain IQ data; a signal detectionmodule communicatively coupled to the data conversion module configuredto detect ongoing time and frequency envelope parameters from thefrequency domain IQ data; an extraction module, communicatively coupledto the signal detection module and the non-transitory data storagebuffer, configured to extract narrowband IQ signal components based onthe detected time and frequency envelope parameters; and anon-transitory storage media configured to receive and store extractednarrowband IQ signal components from the extraction module.
 2. Thecomputer implemented system for IQ data extraction and storage accordingto claim 1, wherein the digital sampling device is a software definedradio.
 3. The computer implemented system for IQ data extraction andstorage according to claim 2, wherein the software defined radioincludes the data conversion module.
 4. The computer implemented systemfor IQ data extraction and storage according to claim 1, wherein thesignal detection module includes instructions executable by a processorto segment and separate frequency domain IQ data from noise.
 5. Thecomputer implemented system for IQ data extraction and storage accordingto claim 1, wherein time and frequency envelope parameters includesignal edges and ranges.
 6. The computer implemented system for IQ dataextraction and storage according to claim 1, further comprising aformatting module wherein the formatting module associates extractednarrowband IQ signal components with time and frequency envelopeparameters.
 7. The computer implemented system for IQ data extractionand storage according to claim 6, wherein the formatting module includesinstructions executable by a processor to tag extracted narrowband IQsignal components with time and frequency envelope parameters.
 8. Thecomputer implemented system for IQ data extraction and storage accordingto claim 7, wherein the processor is central processor.
 9. The computerimplemented system for IQ data extraction and storage according to claim1, wherein the extraction module includes instructions executable by aprocessor to digitally down convert time domain IQ data.
 10. Thecomputer implemented system for IQ data extraction and storage accordingto claim 9, wherein the instructions to digitally down convert frequencydomain IQ data include instructions to frequency shift and down samplethe frequency domain IQ data to extract a narrowband IQ of a narrowsignal.
 11. The computer implemented system for IQ data extraction andstorage according to claim 10, wherein the processor is a graphicprocessor.
 12. The computer implemented system for IQ data extractionand storage according to claim 1, wherein the extraction module includesinstructions executable by a processor to polyphase resample frequencydomain IQ data.
 13. The computer implemented system for IQ dataextraction and storage according to claim 12, wherein the processor is agraphic processor.
 14. The computer implemented system for IQ dataextraction and storage according to claim 1, wherein the extractionmodule includes instructions executable by a processor to digitally downconvert frequency domain IQ data.
 15. The computer implemented systemfor IQ data extraction and storage according to claim 14, wherein theprocessor is a graphic processor.
 16. The computer implemented systemfor IQ data extraction and storage according to claim 1, wherein theextraction module includes a field programmable gate array to digitallydown convert acquired time domain IQ data.
 17. The computer implementedsystem for IQ data extraction and storage according to claim 1, whereinthe extraction module includes a field programmable gate array topolyphase resample frequency domain IQ data.
 18. A method for IQ dataextraction and storage implemented by a machine having one or moreprocessors capable of executing a program of instructions stored on anon-transitory storage medium, the method comprising: acquiring by adigital sampling device time domain IQ data from a data stream of highvolume data; receiving and thereafter storing by a non-transitory datastorage buffer communicatively coupled to the digital sampling deviceacquired time domain IQ data; converting a portion of time domain IQdata to frequency domain IQ data in parallel with the receiving andstoring of the acquired time domain IQ data in the non-transitory datastorage buffer; detecting on an ongoing basis time and frequencyenvelope parameters from the frequency domain IQ data; extractingnarrowband IQ signal components from the acquired time domain IQ data inthe non-transitory data storage buffer based on the detected time andfrequency envelope parameters; and receiving and storing, at anon-transitory storage media, extracted narrowband IQ signal components.19. The method for IQ data extraction and storage according to claim 18,wherein detecting includes segmenting and separating frequency domain IQdata from noise.
 20. The method for IQ data extraction and storageaccording to claim 18, wherein time and frequency envelope parametersinclude signal edges and ranges.
 21. The method for IQ data extractionand storage according to claim 18, further comprising associatingextracted narrowband IQ signal components with time and frequencyenvelope parameters.
 22. The method for IQ data extraction and storageaccording to claim 18, wherein extracting includes digitally downconverting time domain IQ data.
 23. The method for IQ data extractionand storage according to claim 22, wherein extracting includes frequencyshifting and down sampling the frequency domain IQ data.
 24. The methodfor IQ data extraction and storage according to claim 18, whereinextracting includes polyphase resampling frequency domain IQ data. 25.The method for IQ data extraction and storage according to claim 18,wherein extracting includes digitally down converting frequency domainIQ data.